Abrasive article with improved grain retention and performance

ABSTRACT

An abrasive article with improved grain retention and performance and method of making are disclosed. The abrasive article with improved grain retention results in an article with improved performance and longer article life.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/174,240 filed on Apr. 30, 2009 and entitled “ABRASIVE ARTICLEWITH IMPROVED GRAIN RETENTION AND PERFORMANCE”, which is incorporated byreference herein in its entirety.

BACKGROUND

The present invention relates generally to abrasive articles and moreparticularly to an abrasive article with improved grain retention andperformance.

Abrasive articles are typically used in various industries to machineworkpieces by cutting, lapping, grinding, or polishing. The use ofabrasive articles for machining spans a wide industrial scope fromoptics industries, automotive plant repair industries to metalfabrication industries. In each of these examples, manufacturingfacilities use abrasives to remove bulk material to reach designeddimensions, geometry, and surface characteristics of products (e.g.,planarity, surface roughness).

Manufacturers of rough grinding abrasive articles are constantlychallenged to make abrasive articles that meet higher productivity aswell as high performance requirements specified by their customers. Oneparticular reason why manufacturers are challenged to make roughgrinding abrasive articles that meet higher productivity and performancerequirements is that the abrasive articles are subject to not onlymechanical failure due to abrasive grain fracture or attrition or bondfracture, but also to thermal failure at the interface of the abrasivegrain and their surrounding organic bond (i.e., grain pull-out). Inparticular, the high power associated with rough grinding abrasivearticles to remove material without any coolant to remove the heat makesthese articles more prone to the latter type of failure (i.e., thermaldegradation at the interface of the abrasive grain and bond). Thisthermal degradation is even more apparent when using an abrasive grainthat exhibits good resistance to mechanical fractures. Eventually, thethermal degradation weakens the rough grinding abrasive articles,impairing performance and ultimately leading to a shorter life. Thermaldegradation can be especially problematic relative to ultra-thin, drycut-off wheels, which tend to reach thermal degrading temperatures veryquickly at the grain/bond interface.

SUMMARY

In one embodiment, there is an ultra-thin, small diameter cutoff wheel,comprising: a plurality of abrasive grains, an organic bond material andan active filler material. The active filler material comprises aneffective amount of an active endothermic filler material that providesan endothermic reaction at normal dry cutting conditions.

In a second embodiment, there is an ultra-thin, small diameter cutoffwheel that comprises a plurality of abrasive grains and an organic bondmaterial comprising an active endothermic filler material providing anendothermic reaction added thereto. The amount of active endothermicfiller material is in a range of about 12 to about 50 percent by volumeof the bond.

In a third embodiment, there is an ultra-thin, small diameter cutoffwheel that comprises a plurality of abrasive grains and an organic bondmaterial with an active endothermic filler material added thereto toprovide an endothermic reaction that improves grain retention. Theplurality of abrasive grains are selected from the group consisting ofseeded or unseeded sol gel alumina grain, Al₂O₃—ZrO₂ grain andcombinations thereof. The active endothermic filler material is selectedfrom the group consisting of sulfides, low melting point oxides andcombinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an image of an abrasive article according to one embodiment ofthe present invention;

FIG. 2 is a micrograph image of a conventional abrasive article showinga large-number of grain pull-out according to the prior art; and

FIG. 3 is a micrograph image of an abrasive article formed according toone embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring to the drawings, FIG. 1 is an image of an abrasive article 100according to one embodiment of the present invention. In particular,FIG. 1 shows that abrasive article 100 is an abrasive wheel product. Asis known in the art, abrasive wheel products come in a variety of sizessuch as for example, large diameter cutoff abrasive wheel products,medium diameter cutoff abrasive wheel products and small diameter cutoffabrasive wheel products. Generally, large diameter cutoff abrasive wheelproducts have a diameter that is greater than about 1000 mm, mediumdiameter cutoff abrasive wheel products have a diameter that is greaterthan about 400 mm and less than about 1000 mm, while small diametercutoff abrasive wheel products have a diameter that is less than about400 mm. Although the description of the abrasive mix used to formabrasive article 100 that follows is preferably suitable for smalldiameter cutoff abrasive wheel products and more particularly toultra-thin, small diameter cutoff abrasive wheel products that havediameters less than about 250 mm, those skilled in the art willrecognize that the abrasive mix used to form abrasive article 100 mayhave applicability for large diameter cutoff abrasive wheel products andmedium diameter cutoff abrasive wheel products as well.

In one embodiment, abrasive article 100 is an ultra-thin, small diameterbonded abrasive article formed from an abrasive mix that comprisesabrasive grains and an organic bond material with active fillermaterials added thereto such as active endothermic filler material(s).These active endothermic filler material(s) provide an endothermicreaction at “normal dry cutting conditions” to reduce the temperature atthe interface of grains and their surrounding organic bond. Generally,active fillers can be used in bonded abrasives to enhance grindingperformance. Active fillers, also known as reactive fillers, aredesigned to be physically and/or chemically active. They generallyprovide extended, increased cutting rates and coolness of cut. Dependingon various parameters, such as the size and geometry of the abrasivetool, the type of grain and bond used, and the operating conditionsencountered, active fillers can do one or more of the following:

-   -   1.) Decrease the friction between the abrasive grains and the        workpiece being abraded;    -   2.) Prevent the abrasive grains from “capping”, i.e., prevent        metal particles from becoming welded to the tops of the abrasive        grains.    -   3.) Decrease the interface temperature between the abrasive        grains and the workpiece.    -   4.) Decrease the required grinding force.        These actions generally can fall into the following different        mechanisms:    -   1.) Lubrication to reduce friction between the abrasive grain        and the workpiece.    -   2.) Chemical corrosion of metal surface to prevent bonding of        metal onto the tops of abrasive grains or swarf particles from        welding to the workpiece, or by modifying the integrity of the        metal surface to facilitate the formation of chips.    -   3.) Prevention of bond ablation by inhibiting the free radical        process of oxidation of the bond material used to firmly hold        the abrasive grain in place.    -   4.) Controlled bond erosion allows new grains to come into play        and discharge old worn abrasive particles.    -   5.) Heat dissipation by highly endothermic reaction which helps        to dissipate heat away from the grinding interface between the        abrasive grains and the workpiece.

As described herein, using at least one type of active endothermicfiller material that provides an endothermic reaction to reduce thetemperature at the interface of the abrasive grains and theirsurrounding organic bond at “normal dry cutting conditions” results inimproved grain retention or utilization. A result of improved grainretention is that abrasive article 100 will have improved cuttingperformance and longer life than other ultra-thin cutoff abrasive wheelproducts formed from conventional abrasive mixes.

In this embodiment, the abrasive article 100 contains at least one typeof primary abrasive grain selected from the group of abrasive familiesconsisting of seeded or unseeded sol gel alumina and Al₂O₃—ZrO₂. Anon-exhaustive list of abrasive grains from the seeded or unseeded solgel alumina family that may be used in embodiments of this inventioninclude SG grain and NQ grain, commercially available from Saint-GobainAbrasives, Inc. of Worcester, Mass.; 3M321 Cubitron grain and 3M324Cubitron grain, both commercially available from 3M Corporation of St.Paul, Minn.; and combinations thereof. A non-exhaustive list of abrasivegrains from the Al₂O₃—ZrO₂ family that may be used in embodiments ofthis invention include NZ Plus grain, commercially available fromSaint-Gobain Abrasives, Inc. of Worcester, Mass.; ZF grain and ZS grain,both commercially available from Saint-Gobain Abrasives, Inc. ofWorcester, Mass.; ZK40 grain, commercially available from TreibacherIndustry, Inc. of Toronto, Ontario Calif.; and ZR25B grain and ZR25Rgrain, both commercially available from Alcan, Inc. of Montreal, QuebecCA. In one embodiment, the amount of the primary abrasive graincomprises between about 20 to about 100 percent of the total amount ofabrasive grain by volume.

In one embodiment, at least one type of secondary abrasive grain can beblended with the primary abrasive grain to achieve either cost orperformance requirements. The secondary abrasive grain may be selectedfrom the group consisting of ceramic oxides (e.g., coated or non-coatedfused Al₂O₃, monocrystal Al₂O₃), nitrides (e.g., Si₃N₄, AlN) andcarbides (e.g., SiC). In one embodiment, the amount of the secondaryabrasive grain may range from about 80 to about 0 percent of the totalamount of abrasive grain by volume or balance.

In one embodiment, the organic bond material is comprised essentially ofart-recognized organic bond material, such as one or more organicresins—e.g. epoxy, polyester, phenolic, and cyanate ester resins, orother suitable thermosetting or thermoplastic resins. Specific,non-limiting examples of resins that can be used include the following:resins sold by Dynea Oy, Finland, under the trade name Prefere andavailable under the catalog/product numbers 8522G, 8528G, 8680G, and8723G; resins sold by Hexion Specialty Chemicals, OH, under the tradename Rutaphen® and available under the catalog/product numbers 9507P,8686SP, and SP223; and resins sold by Durez Corporation, Tex., under thefollowing catalog/product numbers: 29344, 29346, and 29722. In oneembodiment, the bond material comprises a dry resin material.

In various embodiments, types and amounts of active endothermic fillersare chosen in order to provide an endothermic reaction at “normal drycutting conditions.” The term “normal dry cutting conditions” refersgenerally to those conditions encountered at the grain/bond interface ofa small diameter, ultra-thin cutoff wheel during dry cutting of commonmaterials for which the wheel is designed to cut/grind. An “effectiveamount” of active endothermic filler provides an endothermic reaction atnormal dry cutting conditions. These conditions typically include veryquick ramping to thermal degrading temperatures in excess of 450° C.Thermal degradation can be especially problematic relative toultra-thin, dry cutoff wheels, which tend to transfer heat very quicklyand to reach thermal degrading temperatures very quickly at thegrain/bond interface. In the ultra-thin wheels of the presentapplication, the active endothermic fillers produce an endothermicreaction at the conditions typically encountered during dry cutting and,therefore, reduce the temperature at the grain/bond interface, resultingin much improved grain retention and longer life. In various alternativeembodiments, the active endothermic fillers provide an endothermicreaction when temperature at the grain/bond interface is at least about450° C., or at least about 500° C., or at least about 527° C., or at atemperature which provides an amount of thermal energy greater than theactivation energy necessary to decompose the active endothermic filler.It is noted that when the heating rate is slow or if the grain/bondinterface temperature is too low, exothermic reactions may occur;therefore, the thickness of the abrasive article can play a roll inobtaining the desired endothermic reaction.

In one embodiment, at least one type of active endothermic fillermaterial that provides an endothermic reaction is selected from thegroup of filler types consisting of sulfides and low melting pointoxides. A non-exhaustive list of active endothermic fillers from thesulfide types that may be used in embodiments of the present inventioninclude pyrite, zinc sulfide, copper sulfide, and combinations thereof.A non-exhaustive list of active endothermic fillers from the low meltingpoint oxides types that may be used in embodiments of the presentinvention include bismuth oxide, lead oxide, tin oxide and combinationsthereof. Note that in one embodiment, it is preferable that the activefillers of the low melting point oxides have a melting point below about1000 degrees Celsius.

Those skilled in the art will recognize that various other fillers maybe added to the organic bond material in order to enhance the ability ofabrasive article 100 to cut, lap, grind, or polish. The fillers mayinclude active and/or inactive fillers. A non-exhaustive list of activefillers may include Cryolite, PAF, KBF₄, K₂SO₄, NaCl/KCl, andcombinations thereof. A non-exhaustive list of inactive fillers mayinclude CaO, CaCO₃, Ca(OH)₂, CaSiO₃, Kyanite (a mixture of Al₂O₃—SiO₂),Saran (Polyvinylidene chloride), Nephenline (Na, K) AlSiO₄, wood powder,coconut shell flour, stone dust, feldspar, kaolin, quartz, short glassfibers, asbestos fibers, balotini, surface-treated fine grain (siliconcarbide, corundum etc.), pumice stone, cork powder and combinationsthereof. In a preferred embodiment, an active filler material such asPAF, which is a mixture of K₃AlF₆ and KAlF₄, can be added to the organicbond material in order to corrode metals and reduce the friction betweenthe wheel and workpiece.

In certain embodiments, the formulation of the abrasive mix used to formabrasive article 100 may be as follows. In one embodiment, the abrasivegrains present in this mix may range from about 35 to about 55 percentby volume of the total mix (i.e., excluding porosity). In anotherembodiment, the abrasive grains present in this mix may range from about40 to about 54 percent by volume of the total mix (i.e., excludingporosity). In one embodiment, the organic bond material (e.g., resin) inthis mix may range from about 25 to about 45 percent by volume of thetotal mix. In another embodiment, the organic bond material (e.g.,resin) in this mix may range from about 30 to about 40 percent by volumeof the total mix. In one embodiment, the active endothermic fillermaterial in this mix may be in an amount that ranges from about 5 toabout 30 percent by volume (amount in the total mix). In anotherembodiment, the active endothermic filler material in this mix may be inan amount that ranges from about 5 to about 24 percent by volume (amountin the total mix). In other embodiments, the active endothermic fillermaterial in this mix may be in an amount that ranges from about 12 toabout 50 percent by volume (amount in the total bond). While in otherembodiments, the active endothermic filler material in this mix may bein an amount that ranges from about 12 to about 35 percent by volume(amount in the total bond). The balance will be other fillers thatinclude active or inactive fillers. In one embodiment, the volume ratioof the active filler material providing endothermic reaction to theorganic bond material is in the range of about 0.136 to about 1 (e.g.,resin). In another embodiment, the volume ratio of the active fillermaterial providing endothermic reaction to the organic bond material isin the range of about 0.136 to about 0.67 (e.g., resin).

As mentioned above, in one embodiment, abrasive article 100 is anultra-thin, small diameter cutoff abrasive wheel product. In certainembodiments, abrasive article 100 has a diameter that ranges from about75 mm to about 250 mm and, a thickness of less than about 2.5 mm. Inother embodiments, the thickness of the wheel is between about 0.8 mmand about 2.2 mm. In various embodiments, the wheel can have an aspectratio that ranges from about 40 to about 160. These dimensions makeultra-thin, small diameter abrasive article 100 well suited for drycutting applications. The dimensions and composition of the wheel can bechosen in accordance with the present teachings to provide significantperformance improvement.

As described herein, the abrasive article formed from theabove-described formulation does not suffer from large amounts of grainpull-out like conventional abrasive articles. Abrasive articles formedfrom conventional formulations are adversely affected by large amountsof grain pull-out because the bond between the abrasive grains and bondmaterial in these mixes is unable to withstand the thermal degradationthat arises from the heat input associated with the cutting action ofthe abrasive article. In accordance with the various embodiments of thepresent invention, it has been determined that the temperature at theinterfaces of the grains and their surrounding organic bond at thesurface level of the abrasive article is at the highest and can rangefrom about 600 degrees Celsius to about 1000 degrees Celsius. Theorganic bond material can act as an insulation layer due to its lowthermal conductivity (i.e., less than 2 W/(m·K)) and thus the heat inputfrom the cutting action does not substantially penetrate the depth ofthe abrasive article, where other layers of abrasives reside. Therefore,the temperature at the interfaces of the grains and their surroundingorganic bond at these lower levels, which can be from 250 degreesCelsius to 350 degrees Celsius, is substantially less than thetemperatures at the interfaces of the top surface. Because thetemperature at the interfaces of the grains and their surroundingorganic bond at the surface level is very high, the bond becomes weaker(a typical thermal decomposition temperature of an organic bond materialsuch as a resin is 500 degrees Celsius) and eventually the grains atthis level pull-out and fall from the surface instead of being steadilyworn out through the typical attrition process. The abrasive articleformed from the above-described formulation suffers from less grainpull-out because it is less adversely affected by thermal degradation atthe interfaces of the grains and their surrounding bond material due tothe endothermic reaction occurring to reduce the interfacialtemperature.

Compared to the prior art, the abrasive articles according toembodiments of the present invention are not adversely affected bythermal degradation at the interface of the grains and their surroundingorganic bond material because of the dimensioning of the wheel and theformulation of the specific types of abrasive grains and activeendothermic fillers. In particular, it has been found herein that theuse of the active fillers in the formulations noted above act to providethermal decomposition of the active fillers that result in a coolingeffect that lowers the temperature at the interface of the abrasivegrains and the bond. This counteracts the propensity for rampant thermaldegradation to occur. In addition to the use of these active fillersthat provide an endothermic reaction in the above-noted formulations, ithas been found that the selection and formulation of theabove-identified abrasive grains result in an abrasive product withsignificantly less grain pull-out than the conventional abrasivearticles.

FIG. 2 is a micrograph image 200 of a conventional abrasive articleshowing a large-number of grain pull-out holes 210. Note that for easeof illustration only a few grain pull-out holes 210 are highlighted. Acloser look at image 200 shows that this abrasive article formedaccording to the prior art has a very large number of grain pull-outholes 210. An abrasive article with this many grain pull-out holes willnot perform well and consequently will have a shorter life-span.

In comparison to the conventional abrasive article shown in FIG. 2, FIG.3 shows a micrograph image 300 of an abrasive article formed accordingto embodiments of the present invention. As shown in FIG. 3, theabrasive article formed according to embodiments of the presentinvention has significantly fewer grain pull-out holes than theconventional abrasive article shown in FIG. 2. Although not all of thegrain pull-out holes are highlighted in FIG. 3, it is clear that thereare significantly fewer grain pull-out holes in this figure than in FIG.2.

Because the abrasive article in FIG. 3 has significantly fewer grainpull-out holes, this article as described herein performs cuttingoperations better and lasts longer than conventional abrasive articles.One measurement of performance of an abrasive article is the AbsoluteG-Ratio. The Absolute G-Ratio as described herein is attained bymounting the abrasive article on a portable machine for a dry cuttingapplication that may have a maximum operation speed of about 80 m/s. Aworkpiece material with typical dimensions (e.g., 600 mm (length)×100(width)×6 (thickness) mm) may be clamped by a vise. The number of piecesof cuts from the workpiece material is then counted and recorded into acomputer system along with the diameter of the abrasive article. Anexperienced operator then manually conducts testing by using the grinderto perform cutting operations on the workpiece material. A dataacquisition system connected with the grinder monitors the power andcurrent of the grinder, and cutting time during the testing. The testinglasts until the abrasive article is fully consumed. The diameter of thetested article is then measured and recorded. The weight of theremaining workpiece material is weighed and recorded as well. Thecomputer system using a commercially available software applicationdetermines material removal rate (MRR) and wheel wear rate (WWR). Theapplication calculates the Absolute G-Ratio by dividing MRR by WWR. Ahigher Absolute G-Ratio indicates that the performance of the abrasivearticle is better.

The Relative G-Ratio, which is the ratio of the Absolute G-Ratio ofabrasive article B divided by the Absolute G-Ratio of abrasive article A(reference), is used herein to compare the performance of abrasivearticles. Hence, the Relative G-Ratio of abrasive article A is 1. Ahigher Relative G-Ratio indicates that better performance improvementhas been obtained. Using this approach, it has been determined that theabrasive article formed herein using the above-noted formulations hasRelative G-Ratios that are greater than 1.00. Examples below show thatit is possible to obtain Relative G-Ratio values that range from about1.4 to about 2.4.

EXAMPLES

The following provides particular examples of abrasive articles formedaccording to embodiments described herein.

Example 1

In this example, an abrasive article is formed with the above-notedformulation. About 44 lbs of Al₂O₃—ZrO₂ abrasive grain blended withabout 25 lbs of monocrystal Al₂O₃ abrasive grains was added into amixing container. At least one processing liquid was introduced to thegrains. Herein, about 5 lbs of liquid resin was added into the abrasivegrains. About 11 lbs of powder resin, about 6 lbs of PAF and about 9 lbsof pyrite were prepared in a separate mixing container. The mixture ofthe abrasive grains with the liquid resin was poured into that separatecontainer to mix with the powder resin, PAF, and pyrite mixture. Thenthe abrasive article was formed in the same method as a conventionalabrasive article, such as, for example, the forming methods described inU.S. Pat. No. 6,866,691 B1—which is incorporated by reference in itsentirety. The dimension of the abrasive article was 125 mm in diameterwith 1 mm thickness. The performance of the abrasive article with theabove formulation was tested and its Relative G-Ratio (compared with aconventional abrasive article at the same dimension) was 2.2. Theperformance improvement was due to the fact that the thermaldecomposition of the pyrite reduced the temperature at the interface ofthe abrasive grains and their surrounding organic bond, resulting inimproved grain retention and longer life. Although this disclosure isnot to be limited by proffered theories, it is contemplated that whenthe temperature is higher than 527 degree Celsius, decomposition ofpyrite will be the dominant process due to the high activation energy.

Example 2

In this example, an abrasive article was formed with the above notedformulation. About 68 lbs of seeded or unseeded sol gel alumina Al₂O₃abrasive grain was added into a mixing container. At least oneprocessing liquid was introduced to the grain. Herein, about 5 lbs ofliquid resin was added into the abrasive grain. About 11 lbs of powderresin, about 6 lbs of PAF and about 10 lbs of pyrite were prepared in aseparate mixing container. The mixture of the abrasive grain with theliquid resin was poured into the separate container to mix with thepowder resin, PAF, and pyrite mixture. Then the abrasive article wasformed and tested in the same methods as a conventional abrasive articlewhich has been mentioned above. The dimension of the abrasive article inthis example was 125 mm in diameter with 1 mm thickness. Its RelativeG-Ratio was 1.6. The resulting performance improvement was due to thefact that the thermal decomposition of the pyrite reduces thetemperature at the interface of the abrasive grain and their surroundingorganic bond, resulting in improved grain retention and a longer life.

The following provides a comparative example of an abrasive article notformed according to embodiments described herein.

Comparative Example 1

In this example, an abrasive article was formed with the above-notedabrasive grain, but with different active fillers. In particular, about44 lbs of Al₂O₃—ZrO₂ abrasive grain blended with about 25 lbs ofmonocrystal Al₂O₃ abrasive grain was added into a mixing container.Herein, about 5 lbs of liquid resin was added into the abrasive grain.The only difference between the formulation in this example and theformulation above in Example 1 was that only one type of active filler,PAF, is in the bond formulation. That is, pyrite was not in thisformulation. In particular, about 11 lbs of powder resin and about 13lbs of PAF were prepared in a separate mixing container. The mixture ofthe abrasive grain with the liquid resin was poured into that separatecontainer to mix with powder resin and PAF mixture. Then the abrasivearticle was formed and tested in the same method as described inExample 1. The dimension of the abrasive article in this example was 125mm in diameter with 1 mm thickness. The resulting Relative G-Ratio(compared with a conventional abrasive article at the same dimension)was 1.1. The life of the abrasive article or grain retention did notimprove in the same scale as in Example 1 because the endothermicreaction did not occur during the cutting operation.

While the disclosure has been particularly shown and described inconjunction with preferred embodiments thereof, it will be appreciatedthat variations and modifications will occur to those skilled in theart. Therefore, it is to be understood that the appended claims areintended to cover all such modifications and changes as fall within thetrue spirit of the disclosure.

1. An ultra-thin, small diameter cutoff wheel, comprising: a pluralityof abrasive grains, an organic bond material and an active fillermaterial, wherein the active filler material comprises an effectiveamount of an active endothermic filler material that provides anendothermic reaction at normal dry cutting conditions.
 2. The cutoffwheel according to claim 1, wherein the plurality of abrasive grains areselected from the group consisting of seeded or unseeded sol gel aluminagrain and Al₂O₃—ZrO₂ grain and combinations thereof.
 3. The cutoff wheelaccording to claim 1, wherein the plurality of abrasive grains areselected from the group consisting of SG, NQ, 3M321, 3M324, NZ Plus, ZF,ZS, ZK40, ZR25B, ZR25R, and combinations thereof.
 4. The cutoff wheelaccording to claim 1, wherein the plurality of abrasive grains ispresent in a range of about 35 to about 55 percent by volume/total mix.5. The cutoff wheel according to claim 1, wherein the plurality ofabrasive grains comprise a primary abrasive grain and a secondaryabrasive grain, the primary abrasive grain being selected from the groupconsisting of seeded or unseeded sol gel alumina grains, Al₂O₃—ZrO₂grains and combinations thereof, and the primary grain comprises betweenabout 20 to about 100 percent of the total amount of abrasive grain byvolume.
 6. The cutoff wheel according to claim 1, wherein the activeendothermic filler material is selected from the group of filler typesconsisting of sulfides and low melting point oxides.
 7. The cutoff wheelaccording to claim 6, wherein the active endothermic filler material isselected from the group consisting of pyrite, zinc sulfide, coppersulfide, lead oxide, tin oxide, bismuth oxide and combinations thereof.8. The cutoff wheel according to claim 1, wherein the active fillermaterial comprises Cryolite, PAF, KBF₄, K₂SO₄, and NaCl/KCl andcombinations thereof.
 9. An ultra-thin, small diameter cutoff wheel,comprising: a plurality of abrasive grains and an organic bond materialcomprising an active endothermic filler material providing anendothermic reaction added thereto, the amount of active endothermicfiller material is in a range of about 12 to about 50 percent by volumeof the bond.
 10. The cutoff wheel according to claim 9, wherein theplurality of abrasive grains are selected from the group consisting ofseeded or unseeded sol gel alumina grain and Al₂O₃—ZrO₂ grain andcombinations thereof.
 11. The cutoff wheel according to claim 9, whereinthe plurality of abrasive grains are selected from the group consistingof SG, NQ, 3M321, 3M324, NZ Plus, ZF, ZS, ZK40, ZR25B, ZR25R, andcombinations thereof.
 12. The cutoff wheel according to claim 9, whereinthe plurality of abrasive grains comprise a primary abrasive grain and asecondary abrasive grain, the primary abrasive grain being selected fromthe group consisting of seeded or unseeded sol gel alumina grain,Al₂O₃—ZrO₂ grain and combinations thereof, and the primary graincomprises between about 20 to about 100 percent of the total amount ofabrasive grain by volume.
 13. The cutoff wheel according to claim 9,wherein the organic bond material comprises a dry resin material. 14.The cutoff wheel according to claim 9, wherein the organic bond materialis present in a range of about 25 to about 45 percent by volume/totalmix.
 15. The cutoff wheel according to claim 9, wherein the activeendothermic filler material is selected from the group of filler typesconsisting of sulfides and low melting point oxides.
 16. The cutoffwheel according to claim 9, wherein the cutoff wheel comprises adiameter that ranges from about 75 mm to about 250 mm.
 17. The cutoffwheel according to claim 9, wherein the cutoff wheel comprises an aspectratio that ranges from about 40 to about
 160. 18. The cutoff wheelaccording to claim 9, wherein the cutoff wheel comprises an abrasivewheel.
 19. The cutoff wheel according to claim 18, wherein the abrasivewheel is used for dry cutting applications, where thermal degradation isa primary product wear mechanism.
 20. An ultra-thin, small diametercutoff wheel, comprising: a plurality of abrasive grains and an organicbond material with an active endothermic filler material added theretoto provide an endothermic reaction that improves grain retention,wherein the plurality of abrasive grains are selected from the groupconsisting of seeded or unseeded sol gel alumina grain, Al₂O₃—ZrO₂ grainand combinations thereof and wherein the active endothermic fillermaterial is selected from the group consisting of sulfides, low meltingpoint oxides and combinations thereof.